In order to contact a semiconductor layer, covered with one or more further semiconductor layers, of a semiconductor layer sequence, one or more through-connections, so-called vias, may be used, which extend through the covering semiconductor layers to the semiconductor layer to be contacted. These through-connections are conventionally openings in the semiconductor layer sequence in the form of blind holes which project through a part of the semiconductor layer sequence and which are filled with an electrically conductive material. To prevent a through-connection short-circuiting the semiconductor layers through which it passes, the sidewalls of the openings in which through-connections are arranged are conventionally provided with an electrically insulating layer, such that, within the semiconductor layer sequence, the through-connection is in electrical contact only with the semiconductor layer to be contacted. For better contacting of the material filling the openings, the openings may be provided with contact layers prior to filling.
To produce a through-connection, therefore, firstly an opening has to be produced in the semiconductor layer sequence. Secondly, the opening needs to be provided with an electrically insulating layer and a contact layer, wherein that part of the opening in which the contact layer is arranged must be at least partly free of the electrically insulating layer. To this end, the prior art conventionally uses a plurality of photoresist masks and two or more separate photo levels. This means that different photoresist masks are used one after the other to produce the openings in the semiconductor layer sequence, to pattern the electrically insulating layer and to pattern the contact layer. However, this requires extremely accurate and thus complex process control.